| Type 965M and Type 965P | |
| Country: | United Kingdom |
| Type: | naval long range aircraft warning radar |
| Frequency: | VHF 216-224 MHz |
| Prf: | 200 or 400 p/s nominal |
| Beamwidth: | 12° (horizontal), 40° (vertical) |
| Pulsewidth: | 3.8 μs and 10 μs |
| Rpm: | 10 rpm |
| Power: | 450 kW |
The Type 965 radar was VHF (P band) long-range aircraft warning radar used by warships of the Royal Navy from the 1960s onwards. The Type 965M, Type 965P, Type 965Q and Type 965R were improved versions; the Type 960, 965M and 965Q used the single bedstead AKE(1) aerial, whilst the Type 965P and 965R used the double bedstead AKE(2) aerial.
The 965 is ultimately designed to a May 1950 requirement for a further updated version of the 1945 Type 960. The 960 provided long-range early warning on small ships, but had a very wide beam at 35° horizontal. In 1954 the idea of a general-purpose frigate with the ability to provide some fighter direction arose, which required a radar with a much narrower beam. Marconi responded with the 965, reducing the beam to 12°. Based on WWII technology, the 965 was subject to considerable radar clutter from waves. The Type 965Q and 965R were improvements on the 965M and 965P respectively, adding a COHO-based moving target indication (MTI) mode to suppress clutter. Designed before the introduction of Doppler filtering, it was not able to detect low-level targets against a background, either landforms or high waves.
The lack of a true MTI proved to be a serious problem during the 1982 Falklands War, which ultimately led to the loss of where Argentine aircraft could not be seen against the background of the islands. Similarly, the Type 965 could not detect aircraft flying low; the two Argentine Navy Super Étendards that caused the loss of were not detected by Type 965R radar when they were flying at 30m (100feet), but were shown as contacts by 's Type 965R radar when they popped up to 120feet above sea-level at 45nmi, though it was the UAA1 radar warning receiver that drew attention to the contacts.
The Type 965 radars used radio frequencies that were used by television stations, and therefore caused interference with television (and vice versa) if used near land in Europe. Type 965 was superseded by the Type 1022 radar, which did not have this disadvantage.
During 1954-55, reports on most fleet exercises showed that there was an urgent need for radar picket ships. These would require a suitable radar. The need for such a radar had been raised as a staff requirement in May 1950. In 1955, four radars were considered:
A potential route for the Royal Navy to get the SPS-6C was the Mutual Defense Assistance program (MDAP), but by 1954-5 the programme was running down. In addition, it was thought that getting spares for the SPS-6C radar could be a problem, because the United States Navy considered it obsolescent.The Marconi design was chosen and was named Type 965. The Type 965M was introduced in about 1960, and used the original AKE(1) aerial with an improved receiver and feeder.
A common aerial was used for transmitting and receiving. This was the single bedstead AKE(1) in the Type 965M, and the double bedstead AKE(2) in the Type 965P. The 965M and 965P were integrated with IFF Mk 10. The radar displayed both to an "office display unit" (monitor unit design 44), and up to six remote plan position indicator (PPI) displays.
| +Type 965M and 965P specifications | |||
| Type 965M and 965P [1] [2] [3] | Type 965Q and 965R [4] | ||
|---|---|---|---|
| Frequency | 216-224 MHz | ||
| Wavelength | approximately 1.4m (04.6feet) | ||
| Power output | 450 kW | ||
| Pulse repetition frequency (PRF) | 200 or 400 pulses per second (p/s) nominal | See below | |
| Pulse width | 3.8 μs (with 400 p/s PRF) 10 μs (with 200 p/s PRF) | 4 μs (nominal for MTI working) 10 μs (for non-MTI working) | |
| Aerial rotation speed | 10 revolutions per minute | ||
| Intermediate frequency | 13.5 MHz | ||
| Aerial beam width | 12° (horizontal), 40° (vertical) | ||
| Receiver bandwidth | long pulse 120 kHz, short pulse 330 kHz | long pulse 120 kHz, short pulse (MTI) 330 kHz |
The receiver of the Type 965Q and 965R used "a coherent oscillator (COHO) to provide the coherence in phase between transmission and reception. The COHO is phase locked to the transmitter pulse." With the Type 965Q and 965R, the pulse repetition frequency (PRF) had a number of different settings.
. Norman . Friedman . Norman Friedman . British Destroyers & Frigates, the Second World War and After . 2 . Seaforth Publishing . 2008 . 978-1848320154 . .
. One Hundred Days: The Memoirs of the Falklands Battle Group Commander . Sandy . Woodward . Sandy Woodward . Patrick. Robinson . Naval Institute Press . 1992. 1-55750-651-5 .